制作可触摸的触摸板[LibGdx]

Question

这是我的触控板。

我想要的是：当我触摸触摸板背景（不是旋钮）时，旋钮移动到此位置。代码，我用于github / libgdx / gdx / src / com / badlogic / gdx / scenes / scene2d / ui / Touchpad.java的触摸板

package com.liketurbo.funnyGame;

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 * Copyright 2011 See AUTHORS file.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
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import com.badlogic.gdx.scenes.scene2d.Event;
import com.badlogic.gdx.scenes.scene2d.EventListener;
import com.badlogic.gdx.scenes.scene2d.ui.Widget;
import com.badlogic.gdx.scenes.scene2d.ui.Skin;

        import com.badlogic.gdx.graphics.Color;
        import com.badlogic.gdx.graphics.g2d.Batch;
        import com.badlogic.gdx.math.Circle;
        import com.badlogic.gdx.math.Vector2;
        import com.badlogic.gdx.scenes.scene2d.Actor;
        import com.badlogic.gdx.scenes.scene2d.InputEvent;
        import com.badlogic.gdx.scenes.scene2d.InputListener;
        import com.badlogic.gdx.scenes.scene2d.utils.ChangeListener.ChangeEvent;
        import com.badlogic.gdx.scenes.scene2d.utils.Drawable;
        import com.badlogic.gdx.utils.Pools;

/** An on-screen joystick. The movement area of the joystick is circular, centered on the touchpad, and its size determined by the
 * smaller touchpad dimension.
 * <p>
 * The preferred size of the touchpad is determined by the background.
 * <p>
 * {@link ChangeEvent} is fired when the touchpad knob is moved. Cancelling the event will move the knob to where it was
 * previously.
 * @author Josh Street */
public class Touchpad extends Widget {
    private TouchpadStyle style;
    boolean touched;
    boolean resetOnTouchUp = true;
    private float deadzoneRadius;
    private final Circle knobBounds = new Circle(0, 0, 0);
    private final Circle touchBounds = new Circle(0, 0, 0);
    private final Circle deadzoneBounds = new Circle(0, 0, 0);
    private final Vector2 knobPosition = new Vector2();
    private final Vector2 knobPercent = new Vector2();

    /** @param deadzoneRadius The distance in pixels from the center of the touchpad required for the knob to be moved. */
    public Touchpad (float deadzoneRadius, Skin skin) {
        this(deadzoneRadius, skin.get(TouchpadStyle.class));
    }

    /** @param deadzoneRadius The distance in pixels from the center of the touchpad required for the knob to be moved. */
    public Touchpad (float deadzoneRadius, Skin skin, String styleName) {
        this(deadzoneRadius, skin.get(styleName, TouchpadStyle.class));
    }

    /** @param deadzoneRadius The distance in pixels from the center of the touchpad required for the knob to be moved. */
    public Touchpad (float deadzoneRadius, TouchpadStyle style) {
        if (deadzoneRadius < 0) throw new IllegalArgumentException("deadzoneRadius must be > 0");
        this.deadzoneRadius = deadzoneRadius;

        knobPosition.set(getWidth() / 2f, getHeight() / 2f);

        setStyle(style);
        setSize(getPrefWidth(), getPrefHeight());

        addListener(new InputListener() {
            @Override
            public boolean touchDown (InputEvent event, float x, float y, int pointer, int button) {
                if (touched) return false;
                touched = true;
                calculatePositionAndValue(x, y, false);
                return true;
            }

            @Override
            public void touchDragged (InputEvent event, float x, float y, int pointer) {
                calculatePositionAndValue(x, y, false);
            }

            @Override
            public void touchUp (InputEvent event, float x, float y, int pointer, int button) {
                touched = false;
                calculatePositionAndValue(x, y, resetOnTouchUp);
            }
        });
    }

    void calculatePositionAndValue (float x, float y, boolean isTouchUp) {
        float oldPositionX = knobPosition.x;
        float oldPositionY = knobPosition.y;
        float oldPercentX = knobPercent.x;
        float oldPercentY = knobPercent.y;
        float centerX = knobBounds.x;
        float centerY = knobBounds.y;
        y = centerY;

        knobPosition.set(centerX, centerY);
        knobPercent.set(0f, 0f);
        if (!isTouchUp) {
            if (!deadzoneBounds.contains(x, y)) {
                knobPercent.set((x - centerX) / knobBounds.radius*3.5f, 0);
                float length = knobPercent.len();
                if (length > 1) knobPercent.scl(1 / length);
                if (knobBounds.contains(x, y)) {
                    knobPosition.set(x, y);
                } else {
                    knobPosition.set(knobPercent).nor().scl(knobBounds.radius*3.5f).add(knobBounds.x, knobBounds.y);
                }
            }
        }
        if (oldPercentX != knobPercent.x || oldPercentY != knobPercent.y) {
            ChangeEvent changeEvent = Pools.obtain(ChangeEvent.class);
            if (fire(changeEvent)) {
                knobPercent.set(oldPercentX, oldPercentY);
                knobPosition.set(oldPositionX, oldPositionY);
            }
            Pools.free(changeEvent);
        }
    }

    public void setStyle (TouchpadStyle style) {
        if (style == null) throw new IllegalArgumentException("style cannot be null");
        this.style = style;
        invalidateHierarchy();
    }

    /** Returns the touchpad's style. Modifying the returned style may not have an effect until {@link #setStyle(TouchpadStyle)} is
     * called. */
    public TouchpadStyle getStyle () {
        return style;
    }

    @Override
    public Actor hit (float x, float y, boolean touchable) {
        return touchBounds.contains(x, y) ? this : null;
    }

    @Override
    public void layout () {
        // Recalc pad and deadzone bounds
        float halfWidth = getWidth() / 2;
        float halfHeight = getHeight() / 2;
        float radius = Math.min(halfWidth, halfHeight);
        touchBounds.set(halfWidth, halfHeight, radius);
        if (style.knob != null) radius -= Math.max(style.knob.getMinWidth(), style.knob.getMinHeight()) / 2;
        knobBounds.set(halfWidth, halfHeight, radius);
        deadzoneBounds.set(halfWidth, halfHeight, deadzoneRadius);
        // Recalc pad values and knob position
        knobPosition.set(halfWidth, halfHeight);
        knobPercent.set(0, 0);
    }

    @Override
    public void draw (Batch batch, float parentAlpha) {
        validate();

        Color c = getColor();
        batch.setColor(c.r, c.g, c.b, c.a * parentAlpha);

        float x = getX();
        float y = getY();
        float w = getWidth();
        float h = getHeight();

        final Drawable bg = style.background;
        if (bg != null) bg.draw(batch, x, y, w, h);

        final Drawable knob = style.knob;
        if (knob != null) {
            x += knobPosition.x - (knob.getMinWidth()*2) / 2f;
            y += knobPosition.y - (knob.getMinHeight()*2) / 2f;
            knob.draw(batch, x, y, knob.getMinWidth()*2, knob.getMinHeight()*2);
        }
    }

    @Override
    public float getPrefWidth () {
        return style.background != null ? style.background.getMinWidth() : 0;
    }

    @Override
    public float getPrefHeight () {
        return style.background != null ? style.background.getMinHeight() : 0;
    }

    public boolean isTouched () {
        return touched;
    }

    public boolean getResetOnTouchUp () {
        return resetOnTouchUp;
    }

    /** @param reset Whether to reset the knob to the center on touch up. */
    public void setResetOnTouchUp (boolean reset) {
        this.resetOnTouchUp = reset;
    }

    /** @param deadzoneRadius The distance in pixels from the center of the touchpad required for the knob to be moved. */
    public void setDeadzone (float deadzoneRadius) {
        if (deadzoneRadius < 0) throw new IllegalArgumentException("deadzoneRadius must be > 0");
        this.deadzoneRadius = deadzoneRadius;
        invalidate();
    }

    /** Returns the x-position of the knob relative to the center of the widget. The positive direction is right. */
    public float getKnobX () {
        return knobPosition.x;
    }

    /** Returns the y-position of the knob relative to the center of the widget. The positive direction is up. */
    public float getKnobY () {
        return knobPosition.y;
    }

    /** Returns the x-position of the knob as a percentage from the center of the touchpad to the edge of the circular movement
     * area. The positive direction is right. */
    public float getKnobPercentX () {
        return knobPercent.x;
    }

    /** Returns the y-position of the knob as a percentage from the center of the touchpad to the edge of the circular movement
     * area. The positive direction is up. */
    public float getKnobPercentY () {
        return knobPercent.y;
    }

    /** The style for a {@link Touchpad}.
     * @author Josh Street */
    public static class TouchpadStyle {
        /** Stretched in both directions. Optional. */
        public Drawable background;

        /** Optional. */
        public Drawable knob;

        public TouchpadStyle () {
        }

        public TouchpadStyle (Drawable background, Drawable knob) {
            this.background = background;
            this.knob = knob;
        }

        public TouchpadStyle (TouchpadStyle style) {
            this.background = style.background;
            this.knob = style.knob;
        }
    }
}

线addListener(new InputListener() {...}仅适用于旋钮，如果我能弄清楚触控板的背景是如何工作的，它解决了我的问题。有人知道如何解决这个问题吗？提前谢谢。

Answer 1

您不应该在触控板上添加侦听器。只需限制可以使用触摸板的屏幕触摸区域。

以下是仅在屏幕右半部分激活的代码：

private Touchpad touchpad; 
private Vector2 screenPos = new Vector2();  // position where touch occurs
private Vector2 localPos = new Vector2();   // position in local coordinates
private InputEvent fakeTouchDownEvent = new InputEvent();  // fake touch for correct work
private Vector2 stagePos; // position to fire touch event

private void getDirection() {
    if (Gdx.input.justTouched()) {

        // Get the touch point in screen coordinates.
        screenPos.set(Gdx.input.getX(), Gdx.input.getY());

        if (screenPos.x > Gdx.graphics.getWidth() / 2) { // right half of a screen

            // Convert the touch point into local coordinates, place the touchpad and show it.
            localPos.set(screenPos);
            localPos = touchpad.getParent().screenToLocalCoordinates(localPos);
            touchpad.setPosition(localPos.x - touchpad.getWidth() / 2, localPos.y - touchpad.getHeight() / 2);

            // Fire a touch down event to get the touchpad working.
            Vector2 stagePos = touchpad.getStage().screenToStageCoordinates(screenPos);
            fakeTouchDownEvent.setStageX(stagePos.x);
            fakeTouchDownEvent.setStageY(stagePos.y);
            touchpad.fire(fakeTouchDownEvent);
        }
    } 

}